---
title: "Types of batteries"
subject: "Energy Environment and Society"
chapter: 5
key: "semester_7/energy_environment_and_society:battery-types"
source: https://www.bctengineer.com/q/semester_7/energy_environment_and_society/battery-types
site: BCT Engineering
---

# Types of batteries

Energy Environment and Society · Chapter 5: Energy Storage

- Asked in: 2071 Shrawan, 2 marks
- Video: [How batteries work - Adam Jacobson](https://www.youtube.com/watch?v=9OVtk6G2TnQ) — TED-Ed
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/energy_environment_and_society/battery-types
- Whole chapter: https://www.bctengineer.com/md/semester_7/energy_environment_and_society/chapter-5

## Question

What are the types of batteries?

## Short answer

Batteries are classified as primary (non-rechargeable: alkaline, zinc-carbon) and secondary (rechargeable: lead-acid, NiMH, lithium-ion). Lithium-ion variants (LCO, NMC, LFP) offer high energy density for devices and EVs, while flow batteries store electrolyte externally for grid storage.

## Answer

Batteries are classified in two main ways.

#### 1. By rechargeability
- **Primary batteries (non-rechargeable):** zinc–carbon (dry cell), alkaline, lithium primary, button cells. Used once and thrown away; used in remote controls and clocks.
- **Secondary batteries (rechargeable):** can be recharged many times.
  - **Lead-acid:** flooded, VRLA/AGM, gel (vehicles, inverters, solar).
  - **Nickel–cadmium (NiCd):** durable but toxic cadmium.
  - **Nickel–metal hydride (NiMH):** hybrid cars, rechargeable AA cells.
  - **Lithium-ion** (LCO, NMC, LFP, LTO) and lithium polymer: phones, laptops, EVs, grid storage.
  - **Sodium-ion, sodium–sulphur** and others.
- **Flow batteries** (vanadium redox): electrolyte stored in external tanks, for large grid storage.
- **Fuel cells** are sometimes grouped with batteries, but they are continuous-feed energy converters, not storage devices.

#### 2. By construction
- Wet-cell (flooded), dry-cell, and reserve batteries.

| Type | Nominal voltage | Energy density (Wh/kg, approx.) |
|---|---|---|
| Lead-acid | 2.0 V | 30–50 |
| NiCd | 1.2 V | 40–60 |
| NiMH | 1.2 V | 60–120 |
| Li-ion | 3.6–3.7 V | 100–250 |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. How are batteries mainly classified?
   A. By colour
   B. By weight only
   C. By country
   D. By rechargeability: primary and secondary
   Answer: D. Primary are non-rechargeable, secondary are rechargeable. (Key point: Classification)

2. What is the nominal voltage of a lead-acid cell?
   A. 2.0 V
   B. 1.2 V
   C. 3.6 V
   D. 12 V per cell
   Answer: A. NiCd and NiMH are 1.2 V; Li-ion 3.6-3.7 V. (Key point: Voltage)

3. What is special about flow batteries?
   A. They are non-rechargeable button cells
   B. Electrolyte is stored in external tanks, used for large grid storage
   C. They use no electrolyte
   D. They are used in remote controls
   Answer: B. Vanadium redox is an example. (Key point: Flow battery)